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3
3.Device Handling
This chapter describes the concept of a voice device and how voice devices are named and used.
•Device Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
•Voice Device Names . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.1 Device Concepts
The following concepts are key to understanding devices and device handling:
device
A device is a computer component controlled through a software device driver. A resource
board, such as a voice resource, fax resource, and conferencing resource, and network
interface board, contains one or more logical board devices. Each channel or time slot on the
board is also considered a device.
device channel
A device channel refers to a data path that processes one incoming or outgoing call at a time
(equivalent to the terminal equipment terminating a phone line). The first two numbers in the
product naming scheme identify the number of device channels for a given product. For
example, there are 24 voice device channels on a D/240JCT-T1 board, 30 on a D/300JCT-E1.
device name
A device name is a literal reference to a device, used to gain access to the device via an
xx_open( ) function, where “xx” is the prefix defining the device to be opened. For example,
“dx” is the prefix for voice device and “fx” for fax device.
device handle
A device handle is a numerical reference to a device, obtained when a device is opened using
xx_open( ), where “xx” is the prefix defining the device to be opened. The device handle is
used for all operations on that device.
physical and virtual boards
The API functions distinguish between physical boards and virtual boards. The device driver
views a single physical voice board with more than four channels as multiple emulated D/4x
boards. These emulated boards are called virtual boards. For example, a D/120JCT-LS with 12
channels of voice processing contains three virtual boards. A DM/V480A-2T1 board with 48
channels of voice processing and two T1 trunk lines contains 12 virtual voice boards and two
virtual network interface boards.
3.2 Voice Device Names
The software assigns a device name to each device or each component on a board. A voice device is
named dxxxBn, where n is the device number assigned in sequential order down the list of sorted
voice boards. A device corresponds to a grouping of two or four voice channels.